Gypsy Moth Supression Program


Background Information:

The gypsy moth was introduced into the U.S. in 1869. In Medford Massachusetts that same year, it escaped into the local woodlands. The moth was brought to the U.S. because it was believed that it could be used for silk production. Since that time, the gypsy moth has spread throughout the eastern United States and southern Canada . Early spray programs utilized lead based insecticides and later DDT. These chemicals were effective, however, they were detrimental to the environment. Chemical such as these are no longer being used.



The gypsy moth has four stages of development:

        Gypsy Moth Life Cycle (click on image for larger view):
  • The first stage is the egg. The eggs are commonly found under tree branches, at the junction of the tree trunk and branches, or any place that provides protection from the weather. The egg masses are buff or tan in color and are about the size of a quarter.

  • The second stage is the larvae or caterpillar stage. When first hatched from the egg, the caterpillar is very small. The caterpillar, when fully developed, can grow to about 2- inches long. They are generally very hairy and have two rows of spots. The first five pairs of spots are blue and the last six pairs of spots are brick red color. The rest of the body is gray or black in color.

  • The third stage is the pupae stage. This is when the caterpillar forms a “sack” and begins the process of changing into the moth. These pupae are brown in color and can be found hanging on tree bark or anywhere there is some protection from the weather.

  • The fourth stage is the moth stage. The male moth is usually tan with some black wing markings. The male is a strong flyer. The female is usually off-white in color and usually does not fly well. They can commonly be found fluttering at ground level.

Since their introduction into the U.S. in 1869, the gypsy moth population has run in cycles. The moth population increases about ever 5-10 years. One reason for this cycle is a natural fungus that is found in the soil. This fungus can be contracted by the gypsy moth when it is in the caterpillar stage. The caterpillar will usually die when it contracts this fungus. You may notice caterpillars hanging upside-down on tree branches. The caterpillar is dead and appears to be “dried-out”. This is an example of a gypsy moth that has fallen victim to the natural fungus. The fungus is not harmful to humans or other wildlife. The abundance of the fungus also runs in cycles. As the gypsy moth population increases, so does the abundance of the fungus. There are also other natural gypsy moth controls. There are more than a dozen parasites that attack the gypsy moth. Also some small mammals, birds, and beetles help to control the population.



Gypsy Moth Supression Program:

In addition to the natural controls, many County Conservation Districts have a gypsy moth spray program. The gypsy moth suppression is available here in Elk County, although funding and need for the program varies from year to year. The Elk County suppression program coordinated through the Department of Conservation and Natural Resources (DCNR), Bureau of Forestry. The program is available to any Elk County resident with the following three criteria: 1) The egg masses must be abundant on the property, 2) the property must have a home on it, and 3) the property must have at least 50% tree cover.

The program in Elk County will spray a 500 foot buffer area around the home. Non-residential lots, such as open stands of timber, do not qualify for the program. Each homeowner with a gypsy moth problem should contact the Conservation District. Once contacted, a district representative will conduct an investigation of the property to determine if the property qualifies for the program.

UPDATE: 2012 the gypsy moth populations showed increased signs of expanding populations, however, overall tree defoliation was low and there was no need for a spray program in 2013. The gypsy moth populations will continue to be monitored.


  Click the image for larger view of map: